Motion changing mechanisms



Aug. 10, 1965 c. F. PRINS 3,199,361

MOTION CHANGING MECHANISMS Filed March 12, 1962 6 Sheets-Sheet l Aug.10, 1965 c. F. PRINS MOTION CHANGING MECHANISMS 6 Sheets-Sheet 2 FiledMarch 12, 1962 v Aug. 10, 1965 c. F. PRINS MOTION CHANGING MECHANISMS 6Sheets-Sheet 5 Filed March 12, 1962 Aug. 10, 1955 g, F, Ns 3,199,361

MOTION CHANGING MECHANISMS Filed March 12, 1962 6 Sheets-Sheet 4 Aug.10, 1965 c. F. PRINS 3,199,361

MOTION CHANGING MECHANISMS Filed March 12, 1962 6 Sheets-Sheet 6 Aug.10, 1965 c. F. PRINS 3,199,361

MOTION CHANGING MECHANISMS Filed March 12, 1962 6 Sheets-Sheet 5 UnitedStates Patent 3,199,361 MUTEON CHAN'GENG MECHANHSMS Christian F. Pains,Olifantsvlei 16 Dist. H3 R0. Eiirenhof, via Johannesburg, Transvaal,Republic of South Africa Filed Mar. 12, 1962, Ser. No. 178,863 iaimspriority, application Republic of South Africa,

Mar. 14, 1961, 1,026/61 7 Claims. (Cl. 74-124) This invention rel-atesto motion changing mechanisms of the kind in which a rotary motion istransformed into an oscillating or reciprocating movement. In particularthe invention is intended for use in speed reducing de vices asdescribed below.

Speed reducing devices to which the invention relates include a driveshaft providing one or more cylindrical cams eccentrically locatedrelative to the shaft and which act to oscillate straps, the pointswhere the straps engage the bearing surfaces of the cams being in thenature of followers. The straps embrace an output shaft in such a mannerthat the oscillation of the followers at the driver causes rotation ofthe output shaft. The cycle of operation is such that on the rise of afollower the associated strap grips the output shaft and turns it apredetermined amount, and on the fall of the follower the strap releasesits grip and returns or is returned to a neutral position. Speedreducers of this character have been the subject of study for manyyears.

The amplitude of oscillation of the follower, the number of strapsemployed and the speed of rotation of the drive shaft determine thespeed of the output shaft.

Various attempts have been made to provide an effective control meansfor a speed reducer of the kind in question, one which would enable asubstantial range of output speeds to be obtained for a fixed speed ofthe drive shaft, but to the knowledge of the applicant no satisfactoryspeed varying device has been provided. An object of the presentinvention is to provide a speed control mechanism which will enablevariations of the output speed to be obtained for a constant drive shaftspeed. Other objects of the invention will appear as the specificationproceeds.

The invention is also directed to the provision of means merely for thepurpose of Changing rotary motion of a drive shaft into oscillatorymotion of a follower, the means having special characterizing featuresas will appear hereunder.

According to the invention, there is provided apparatus for theconversion of rotary motion into reciprocating motion which includes adrive shaft, a first cylindrical eccentric mounted on and fixed to theshaft, a second cylindrical eccentric having a cylindrical recess forthe the snug accommodation of the first eccentric. The two eccentricsare rotatable relatively to one another to vary the eccentricity of thesecond eccentric relative to the axis of rotation of the shaft. Followermeans is provided for the second eccentric which is adapted forundergoing oscillation upon eccentric rotation of the second eccentricfor having the oscillation converted to rotary movement. The apparatusfurther comprises a flyweight system adapted to orbit the shaft underthe influence of centrifugal force, and a link-age system coupling theflyweight system to both eccentrics, the linkage system includingelements rigid with respective eccentrics, which elements are relativelymovable upon radially outward movement of the flyweight system toincrease the eccentricity of the second eccentric, the element rigidwith the second eccentric being effective to convert drag which isimparted to the second eccentric by the follower means into reverserelative movement of the elements.

Also according .to the invention the elements of the 3,19,361 PatentedAug. 10, 1965 ice linkage system are arms rigidly coupled to the eccen-.trics, the arms diverging radially, the flyweight system includinglinks pivotally connected together and to the free ends of the arms.

Preferably the apparatus provides tWo identical first and secondeccentric sets mounted in anti-phase on the shaft, and a flywheel barmounted on the shaft having opposed radially disposed guides forconstraining pivotal movement of the links of the flywheel system.

Control means may also be provided for varying the orbital radius of thesystem in order to control the throw of the follower means, the controlmeans including a stop rigid with the shaft and .a mating stop rigidwith a second eccentric, which stops on engagement, lock the shaft andsecond eccentrics against relative movement and limit the flywheelsystem to rotate in a predetermined orbit, and a regulator for adjustingthe angular setting of the stops when the shaft is stationary. Forsituations in which the device is to be used as a speed changingmechanism the followers of the follower means are preferably rigid withstraps embracing an output shaft and which act to rotate the shaftaccording to the oscillatory rise and fall of the followers.

Further according to the invention the elements of the linkage systemmay be arms rigid with the first and second eccentrics, the arms beingcoupled to the flywheel system through a flexible link slidably engagingat least one weight such that relative movement of the eccentrics actingto increase or decrease the effective length of the link alters theorbital radius of the weight about the axis of the shaft.

The flexible link arrangement is preferably one in which a plurality ofweights is symmetrically disposed about the shaft and all the weightsare engaged by the link.

According further to the invention a first and second eccentric set ismounted on the shaft to each side of a common flyweigh-t system, theeccentric sets being mounted in antiaphase.

In a further arrangement of the invention the controller includes ahelically threaded portion on the shaft, a sleeve covering the threadedportion of the shaft, fast with the shaft stop and having at least oneaxial slot, and a traveller nut on the shaft with a projection engagingin the slot, movement of the nut along the shaft acting to turn thesleeve to alter the angular relationship of the stops.

Preferably the sleeve is enclosed in a rotatable housing adapted onrotation to cause the desired movement of the traveller nut.

The invention also provides for a plurality of first and second camsmounted in sets on the shaft with the followers to operate in balancedphase relationship.

In order to illustrate the invention two examples are describedhereunder with reference to the accompanying drawings in which FIGURE 1is a perspective view of a device for reducing speed,

FIGURE 2 is a perspective view of a second form of speed reducer inaccordance with the invention with its cover plate removed,

FIGURE 3 is a sectional side view of the device of FIGURE 2,

FIGURE 4 is a sectional end elevation on the line IVIV of FIGURE 3,

FIGURE 5 is a sectional side elevation on the line V-V of FIGURE 3,

' FIGURE 6 is a section on the line VIVI of FIG- URE 5 with the lefthand cover plate and locating washer removed,

FIGURE 7 is a similar view to that of FIGURE 6 with the washer inposition,

FIGURE 8 is a section on the line VIIIVIII of FIGURE 5,

FIGURE 9 is a perspective with parts broken away showing the stop meansthrough which the output speed may be adjusted, and

FIGURE 10 is a section with parts broken away showing an alternativearrangement for controlling the output speed.

Referring to FIGURE 1, the device includes an input shaft Ill on whichis mounted in anti-phase two spaced cylindrical first eccentrics I2 andon these elements ride second cylindrical eccentrics 13 which are againdisposed in anti-phase on their respective first eccentrics. By movementof the first and second eccentric sets relative to one another so theeccentricity of the second eccentric rela-tive'to the axis of rotationof the shaft may be 'varied through a range depending upon designrequirements. In the embodiment the variation is allowed to take placein a range which at one end involves no eccentricity, a position whichcorresponds to a state where the follower 14, riding on the eccentricsurface 15, remains stationary, i.e. the follower has no throw.

In order to adjust the eccentricity of the second eccentric through therange in order to control the throw of the followers 14, the eccentricsare associated with flyweight systems which orbit the drive shaft 11.Thus, in the example under consideration, the first eccentric I2 is fastwith the shaft 11 and from the shaft, and fast therewith, an arm 16projects; in other words the arm 16 is directly or indirectly rigidlycoupled to the first eccentric. A similar arm 17 projects outwardly fromthe second eccentric l3 and the ends of arms 16 and 17 are pivotallyconnected, respectively, to links 13 and 19 which in turn are joinedpivotally at 23. The combination of links 18 and I9 constitute theflyweight system for the two eccentrics l2 and I3. Exactly the samearrangement is provided for the second pair of elements 12 and I3 andthe two flyweight systems are constrained for movement in guides 21provided by the flywheel bar 22 mounted on the shaft llll.

9n rotation of the shaft 11 centrifugal force commences to act on theflyweight systems as they orbit the shaft axis; and the effect of theradially outward movement of the systems is to turn the eccetrics 312and 13 relative to one another through arms 16 and 17, thereby toincrease the eccentricity of the second eccentric I3 relative to theaxis of the shaft 11. In some arrangements the outward travel of theflyweight systems is purely a function of the speed of rotation of theshaft ll; i.e. the faster the shaft turns the greater the radiallyoutward movement of the system and this movement is ultimately checkedby the mechanical design of the device or by load conditions imposed onthe eccentric surface by the follower 14.

In the embodiment, however, the throw of the follower is speciallycontrolled to suit output requirements at shaft 23, for in this case theoscillatory motion of the followers is transformed back again into arotary motion to make the device into a speed reducer.

For controlling the radially outward movement of the flyweight systemand thereby the throw of the follower, the eccentric 13 is equipped witha stop 24 which is adapted to engage with a mating stop 25 fast with theshaft 11 through adjustable boss 26. The throw of the eccentric dependsupon the. angular relationship of the part a rotary movement to thisshaft as its follower oscillates on the eccentric track The strap isadapted .to move through a cycle during oscillation of the followerwhich includes gripping the shaft boss 28 and rotating it apredetermined amount as the follower rises on the eccentric track, andreleasing the grip and returning to a neutral position as the followerfalls on the track. It will be noted in the example that the followerlid is double headed in the sense that it is of a forked character. Thereason for this is that on the fall of the follower the lower section ofthe fork is engaged by the eccentric to ensure that the strap isreturned to the neutral position.

Strap type speed reducers are per se known and it is not proposed todescribe in detail the method by which they change the reciprocatorymotion of the followers into rotation of shaft 23 Sufilce to say thattheir action is analogous to the gripping of a shaft with clenched handswherein the shaft is gripped and turned, Whereafter the hands return toa neutral position preliminary to a further gripping step. If the handswork in anti-phase the shaft is kept rotating. This is what happenswhere a plurality of straps is employed.

Assuming now that the shaft 11 is about to be started up. Stop is set togive the desired oscillation of the follower I4; i.e. by fixing the stopat the correct angular relationship relative to the stop 24. On startingin the direction of arrow 29 the immediate reaction is to draw theflyweight system inwardly because of the movement of arm 16. Speedbuilds up and centrifugal force commences to act on the flyweight systemcausing it to move radially outward. This outward movement is finallychecked since the effect of the movement is to rotate the arms 16 and 17in anti-phase until the stops 24 and 25 abut. Up to this stage the throwof the follower has gradually increased and when the stops engage nofurther increase of the throw is possible since it is not possible forthe stop 24 to over-ride the stop 25.

The unison of action of the two sets of eccentrics is maintained throughthe flywheel bar 22 which operatively couples the systems together.

The driven shaft 23 is now kept in motion and should any overload occurthe device tends of its own accord to reduce the eccentricity untilultimately a stage can be reached when the follower has no oscillatorymovement at all. The manner in which this occurs is as follows:

The effect of an overload is to turn the follower 14 into a brake padwhich endeavours to check the movement of the underlying eccentric 13.Arm 17 nowhas a dragging effect on the flyweight system tending toovercome the effects of centrifugal force and the extent of the dragwilldepend upon the braid ng load imposed on the eccentric I3 by thefollower. If the load is great enough the stage will be reached in whichthe drag effect will completely overcome the effects of centrifugalforce and the arms 16 and 17 will be moved into a position in which thecentral axis ofthe eccentric l3 and the corresponding axis of the shaftlll are co-incident. At this point the follower 14 is stationary.

Clearly the bore in the second eccentric 13 which accommodates the firsteccentric 12 must be eccentrically disposed relative to the central axisof the second eccentric for otherwise no adjustment of the eccentricityof the two relevant axes becomes possible. The greater the eccentricityof the bore the greater the variation of follower throw which becomespossible.

In the preferred forms of the invention the device is accommodated in acasing which constitutes an oil bath as will appear from the discussionhereunder of the second embodiment illustrated in the remaining figures.

FIGURE 2 is a perspective which illustrates the appearance of a speedreducer according to the invention with its casing 31 having its top 32removed. Top 32 enables repairs to be effected on the working parts ofthe device although some repairs are possible through inspection port33. Port 33 is closed by a transparent viewing panel 34. In FIGURE 3, asectional side elevation is illustrated which shows a strap 35articulated at 36 and suitably held at 37, the strap embracing theoutput shaft 38 and strap boss arrangement The operation of the strap issubstantially as described in the previous example. With the rise of thefollower the strap grips the shaft through the boss arrangement 39 andturns the shaft 38 a predetermined amount, and on the fall of thefollower the grip on the boss is released and the strap returns to aneutral position. By using two straps operating in anti-phase the shaftis kept rotating. Clearly a greater number of straps may be employed ifdesired. FIGURE 4 is a sectional end view on the line IV--IV of FIGURE 3from which it will be seen that the shaft 38 is supported in ballbearings 40 in the casing 31.

Adjustment of the strap in relation to shaft 38 is accomplished by thearrangement shown at 41 which illustrates diagrammatically an adjustingmeans. Hinge arrangements may be used if desired. Spring means 42 servesto bias the strap to a neutral position.

FIGURE 3 also shows aspects of the drive section of the device.Reference 43 indicates the drive shaft, 44 the first eccentric fast withthe shaft, 45 the second eccentric mounted on the first eccentric asdescribed with reference to the first example and the follower is shownby reference 46. In this example the follower is of a differentcharacter from the forked arrangement described previously. Here thefollower is a member which is bored out to accommodate a ball or rollerrace 47 which in turn is mounted over the second eccentric 45. Thefollower is linked to the strap 35 pivotally at point 48. As in theprevious example two straps are employed which work in antiphase.

Reference 50 refers to a fiyweight system which is illustrated ingreater detail in FIGURE 5 and which is used in the control of the throwof the followers. In FIGURE 5, the drive shaft 43 is shown located inroller bearings 51 in the side walls of the casing 31 and the shaft isseen to have first eccentric 44 and concentric boss 53 fast therewith.On each eccentric 44 there is mounted the second eccentric 45 which inturn has the follower 46 mounted on it. Pivot point 48 for the strap andfollower oscillates in the direction of arrows 54. A roller bearing 52is used at the pivot point.

In the second form of the invention the second eccentric 45 isassociated with an arm 55 which is the equivalent of arm 17 shown in theexample of FIGURE 1, while the arm 16 of FIGURE 1 finds its equivalentin the concentric boss 53. In the arrangement of FIG- URE 1 eacheccentric set had a flyweight system of its own with both systems linkedtogether through the flywheel bar 22; in the arrangement underconsideration the eccentric sets share a common flyweight arrangement5%.

The flyweight arrangement 50 includes spaced side plates 56 which aremounted on the boss 53 and which are held in spaced relationship by theperipheral ridges 57 on the boss 53. Each side plate will be seen toprovide a hub section 58 and each hub section accommodates half of aflywheel 59, the two halves being keyed together by screw means 60 andscrew 61 acting to lock the flywheel to the side plates. The flywheel 59is formed with spaced radial legs 62 (see particularly FIGURE 6) betweenwhich are defined spaces 63 for accommodating planet weights 64, and afurther space 65 exists between the leg sections provided by each halfof the flywheel for the location of chain 66. The flywheel is fast withthe boss 53 and is locked to the arms 55 of the eccentric elements 45 bythe engagement of pivot shoes 67 on the arms sliding in slot arrangement68 in the side plates 56.

Chain 66, as mentioned in the previous paragraph, is located in thespaces 65 defined between mating sections of the flywheel legs 62 and isalso accommodated in similar spaces 69 defined between the limbs 49 ofweights 64 which in section are of substantially U-shaped character aswill be seen in FIGURE 5. In passing through the spaces '65 the chain isthreaded under pins 70 in the flywheel legs and in the spaces 69 in theweights it is threaded over similar pins 71. Pins 71 have their endsprojecting beyond the sides of the weights to be accommodated inradially disposed grooves 72 found in the inside faces of the sideplates 56. Each weight has an additional pin arrangement 73 which isalso accommodated in the groove or guide track 72 for stabilisingpurposes.

The chain is linked at one end to the boss 53 in the space between theridges 57 and, as FIGURE 6 will show, the series of holes 74 in theridges 57 enable the chain to be secured on the boss in any one ofseveral positions. It will be seen that a central upstanding ridge 75 isprovided in the space between ridges 57 and the purpose of this ridge isto provide a bearing surface for the chain which in this example is ofthe bi-cycle type. From the boss the chain is lead over the first pin 76fast with the flywheel, then over the first weight pin 71, then underthe first flywheel leg pin 70 and so on until the other end of the chainis reached. The free end of the chain is then anchored to the adjacentflywheel leg pin 76. By this means it may be said that one end of thechain is securely anchored to the first eccentrics 44, albeit throughthe boss 53 which will be seen to be fast with the eccentrics 44, and tothe second cam elements 45 through the flywheel legs which are fast withthe side walls 56 and which are in turn coupled to the eccentrics 45through arm 55 and shoes 67. The position is thus basically identical tothat described in the first example in as much as each of the eccentricsis coupled into a flyweight system which on rotation acts to move theelements relatively to one another to increase the eccentricity of thelongitudinal axis of the second eccentric relative to the central axisof the shaft 43.

To ensure that on outward movement of the weights 64 they all move inunison to maintain balance in the flyweight system, special washermembers 77 are located between the flywheel and the side plates, thewashers being free to rotate on the boss sections 78 of the flywheelquite independently of the flywheel. As will be seen in FIG- URE 7, thewashers are provided with slanted guide channels 75 through which passthe ends of pins 71. As the weights move outwardly the pins tend to turnthe washers so that they may ride in the grooves or guide tracks 72 inthe side plates. Thus all the weights are main tained at the same radialspacing from the boss 53.

As in the previous example, the eccentricity of the central longitudinalaxis of the second eccentric 45 relative to the long axis of the shaftis controlled by the setting of stops 80 and 81 on the eccentric 45 andshaft respectively. Before proceeding to describe the stop controlmechanism in detail it is proposed to describe the operation of thespeed reducer, for up to this stage the major description is over, thereremaining simply details of the modes of controlling the eccentricity.

By fixing the relative positions the two stops 80 and 81 would assumewhen the shaft 43 is stationary so more or less of the chain 66 is woundon to the boss 53. The smaller the amount of chain held wound on theshaft the greater the ultimate outward movement of the flyweights andhence the greater the eccentricity. This will be apparent from aconsideration of FIGURES 5 and 6. If stop 81 is turned clockwise acertain amount of slack occurs in the chain which is subsequently takenup as the weights move out. Likewise, if the stop is turnedanti-clockwise more chain is wound on to the boss 53 and the orbitalradius of the weights is reduced.

' On rotation the weights move out according to the available slack inthe chain and the outward movement of the weights acts to turn theeccentrics relatively to one another until the stops 8t) and 81 engage.This engagement prevents stop 36 overriding stop 81 and fixes the throwof the follower.

On the occurrence of overloads the action of follower 46 is to exert abraking force on the eccentric 45 and this force tends to retard arm 55.In the event the stops 80 and 81 part with the shaft acting now to windin some of the chain thereby reducing the orbital radius of the weights,and simultaneously reducing the eccentricity of the eccentric axisrelative to the axis of the shaft. If the load is of a drastic characterthe eccentricity may be reduced until it is eliminated altogether atwhich stage the follower has no throw.

As mentioned several times in the previous portion of the description,the throw of the follower determines the speed of rotation of the outputshaft and control of the output speed is obtained by adjusting theeccentricity of the axis of the second eccentric 45 relative to the axisof the shaft 43. Two types of control mechanism are illustrated inconnection with the embodiment of the invention shown in FIGURES 2 to10, one enabling speed changes at the output shaft to be effected duringrotation of the drive shaft 43, and the other which merely enablesadjustments to be made with shaft 43 stationary.

Dealing firstly with the control mechanism which permits adjustmentsduring rotation of the shaft 43. The control mechanism is bestillustrated in FIGURES 5 and 8. The drive shaft 43 is mounted in rollerbearings 51 between which and the shaft are bored bosses 32 and 83. Boss82 is keyed to shaft 43 by key 84 and provides a stop '85 adapted toengage stop as on eccentric 45 of the left hand cam set. The stops 35and $6 correspond to the stops 81 and Stl except that they are 180degrees apart when abutment takes place. Stop 81 is fast with boss 83and this boss is not directly keyed to shaft 43.

The shaft 43 projects through the casing 31 on the right hand side ofFIGURE 5 and the projecting portion 37 has a helical thread 83 cut intoit. On the thread there is mounted a threaded spider 89 having arms 99which project through axial slots 91 in a cage arrangement 92 fast withthe boss 33. The cage is inturn located in a housing 93 which isinternally threaded at 94 and which is rotatably anchored between plates95 and 96 by the engagement of flange 97 in a complemental space definedbetween the two plates. right hand side is constrained against axialmovement by means of flange 93 on plate 96 and flange 99 on boss 83. Inthe space between the housing and the cage there is a nut 1% which maybe moved axially on rotation of the housing. The nut is releasablysecured to a ring 1M so as to define a U-shaped space H32 in which islocated the extremities of the spider arms id and a ball race 1%. Theprovision of race M53 permits the spider to rotate while the nut movesaxially on rotation of housing 93. To adjust the eccentricity of thecentral axis of the eccentrics 45 relative to the axis of the driveshaft 43, the nut 1% must be moved to the desired position on the cage.

92. This is achieved by turning housing 93. As the nut is moved axiallyso the spider is pulled axially along with it and as the spider isthreaded on the helical section 88 the spider is forced to turn on theshaft thereby rotating the cage 92, and moving the stops apart when theeccentricity is to be increased. If the eccentricity is to be decreasedthe stop Sl forces the stop 80 to retard eccentric 55 thereby to bringabout slack in the chain 66 which is wound on to the boss 53 to reducethe orbital radius of the flyweight weights. A reduced throw of thefollower is thus accomplished with consequent reduction in the speed ofrotation of the output shaft 38. The adjustments effected by the controlsystem referred to above may be achieved while the shaft 43 is keptrotating. The purpose of the stops $5 and 36 is to prevent an overrun,whereby when overloads occur the decrease of eccentricity to zero isaccompanied by the danger of the eccentricity increasing in the reversedirection. In other words, when zero eccentricity is reachedcorresponding to maximum overload conditions the stops 85 and 86 engage.When the overload is removed stops iii) and 81 are urged towards oneanother again and stops 85 and 86 part an equivalent amount. Thus it maybe said that while the members of one set of stops are being urgedRoller bearing 51 on theoperatively towards one another the members ofthe other set are opening up. In the normal operating condition, stops30 and 31 are urged together and in the neutral or inoperative, ormaximum overload, conditions stops and 86 abut. Reference ltldindicatesa sealing ring to prevent the escape of oil from the casing.

in FIGURE 10 an alternative control mechanism is shown, a mechanismwhich does not permit adjustments of the follower throw to be effectedwhile the shaft 43 is rotating. In this case stop 33 and its associatedboss 83 are fast with an adjusting disc which may be locked to acorresponding disc res fast with the shaft 43 through screw means 107 toadjust the spaced relationship of the stops 80 and 81 when the shaft isstationary.

Many more examples of the invention exist each differing from the otherin matters of detail but in no way departing from the principles set outin the oppended claims. The essence of the invention is the arrangementby means of which the throw of the follower may be adjusted so thatdevices employing the equipment have a control over the end function. inboth embodiments the motion changing mechanism has been used for speedreducing purposes and in these cases speed control depends upon theduration that the straps grip the shaft during each cycle of the strapfollower. Clearly the frequency of oscillation of the followers remainsthe same for the same speed of rotation of the drive shaft withoutregard to the follower throw. The effect of the throw is merely to alterthe period in each cycle in which the strap is doing effective work inturning the output shaft. With small throws the effective working periodin each cycle is small so that the linear movement of the output shaftis correspondingly small. At the other extreme of the permissible rangeof throws, i.e. with large follower oscillations the movement is muchgreater. In other words for a constant frequency of oscillation but withdiffering.

follower throw the speed of rotation of the output may be varied.

I claim: I

1. Apparatus for the conversion of rotary motion into reciprocatingmotion, said apparatus comprising a drive shaft, :1 first cylindricaleccentric mounted on and fixed to the shaft, a second cylindricaleccentric mounted snug- 13/ on the first eccentric, the first and secondeccentrics being rotatable relative to one another to vary theeccentricity of the second eccentric relative to the axis of rotation ofthe shaft, follower means adapted for undergoing oscillation uponeccentric rotation of the second eccentric, a flyweight system adaptedto orbit the shaft under the influence of centrifugal force, saidflyweight system including a linkage system coupled to at least one ofsaid eccentrics, the linkage system including elements respectivelysecured for rotation to at least said one eccentric, which elements arerelatively movable upon radially outward movement of the flyweightsystem to increase the eccentricity of the second eccentric with respectto the shaft, the reaction of said follower means on said secondeccentric tending to move said second eccentric into concentric relationwith said shaft.

2. The apparatus as claimed in claim 1 in which the elements of thelinkage systems are arms respectively secured for rotation with thefirst and second eccentrics, the arms being coupled to the flyweightsystem through a flexible link slidably engaging at least one weightsuch that relative movement of the eccentrics acting to vary theeffective length of the link alters the orbital radius of the weightabout the axis of the shaft.

3. The apparatus a claimed in claim 2 comprising a plurality of weightsincluding the first said weight symmetrically disposed about the shaft,all of the weights being engaged by the flexible link.

4. Apparatus for the conversion of rotary motion into reciprocatingmotion, said apparatus comprising a drive shaft, a first cylindricaleccentric mounted on and fixed to the shaft, a sceond cylindricaleccentric snugly mounted on the first eccentric, the two eccentricsbeing rotatable relatively to one another to vary the eccentricity ofthe second eccentric relative to the axis of rotation of the shaft,follower means for the second eccentric adapted for undergoingoscillation upon eccentric rotation of the second eccentric, a fiyweightsystem adapted to orbit the shaft under the influence of centrifugalforce, said flyweight system including a linkage system coupled to botheccentrics, the linkage system including an element rigid with at leastone eccentric, which elements are relatively movable upon radiallyoutward movement of the iiyweight system to increase the eccentricity ofthe second eccentric with respect to the shaft, the reaction of saidfollower means on said second eccentric tending to move said secondeccentric into concentric relation with said shaft, said control meansfor varying the orbital radius of the flyweight system in order tocontrol the throw of the follower means, the control means including astop rigid with the shaft and a mating stop rigid with the secondeccentric such that upon engagement of the stops the shaft and secondeccentric are locked against relative movement and hold the fiyweightsystem to rotation in a predetermined orbit, and regulator means foradjusting the angular setting of the stops when the shaft is stationary.

lit

5. The apparatus as claimed in claim 4 in which the regulator meansincludes a boss arrangement with which the stop on the shaft is rigidand means for detachably securing the boss in any desired position onthe shaft.

6. The apparatus as claimed in claim 5 in which the regulator meansincludes a helically threaded portion on the shaft, a sleeve coveringthe threaded portion on the shaft and rigid with the boss and having atleast one axial slot, and a traveller nut on the shaft with a projectionengaging in the slot such that movement of the nut along the shaftcauses the sleeve to turn and thereby alter the angular relationship ofthe stops.

7. The apparatus as claimed in claim 6 comprising a rotatable housingenclosing the sleeve and adapted upon rotation to move the nut.

References Cited by the Examiner UNITED STATES PATENTS 687,566 11/01Johnson 74-l17 2,006,779 7/35 Terrell 74571 2,592,237 4/52 Bradley.

BROUGHTON G. DURHAM, Primary Examiner.

1. APPARATUS FOR THE CONVERSION OF ROARY MOTION INTO RECIPROCATINGMOTION, SAID APPARATUS COMPRISING A DRIVE SHAFT, A FIRST CYLINDRICALECCENTRIC MOUNTED ON AND FIXED TO THE SHAFT, A SECOND CYLINDRICALECCENTRIC MOUNTED SNUGLY ON THE FIRST ECCENTRIC, THE FIRST AND SECONDECCENTRICS BEING ROTATABLE RELATIVE TO ONE ANOTHER TO VARY THEECCENTRICITY OF THE SECOND ECCENTRIC RELATIVE TO THE AXIS OF ROTATION OFTHE SHAFT, FOLLOWER MEANS ADAPTED FOR UNDERGOING OSCILLATION UPONECCENTRIC ROTATION OF THE SECOND ECCENTRIC, A FLYWEIGHT SYSTEM ADAPTEDTO ORBIT THE SHAFT UNDER THE INFLUENCE OF CENTRIFUGAL FORCE, SAIDFLYWEIGHT SYSTEM INCLUDING A LINKAGE SYSTEM COUPLED TO AT LEAST ONE OFSAID ECCENTRICS, THE LINKAGE SYSTEM INCLUDING ELEMENTS RESPECTIVELYSECURED FOR ROTATION TO AT LEAST SAID ONE ECCENTRIC, WHICH ELEMENTS ARERELATIVELY MOVABLE UPON RADIALLY OUTWARD MOVEMENT OF THE FLYWEIGHTSYSTEM TO INCREASE THE ECCENTRICITY OF THE SECOND ECCENTRIC WITH RESPECTTO THE SHAFT, THE REACTION OF SAID FOLLOWER MEANS ON SAID SECONDECDENTRIC TENDING TO MOVE SAID SECOND ECCENTRIC INTO CONCENTRIC RELATIONWITH SAID SHAFT.